The magnetic-recording, hard-disk-drive (HDD) industry is extremely competitive. The demands of the market for ever increasing storage capacity, storage speed, and other enhancement features compounded with the desire for low cost creates tremendous pressure for improved performance of the HDD. Therefore, engineers and HDD designers are constantly striving to eliminate performance detractors from the HDD design.
Just a few performance detractors that affect the HDD include adjacent track interference, poor soft error rate, compromised data integrity, long track-seek settling times, side reading and off-track recording, which often originate from new, unexpected causes. To overcome these performance detractors, engineers have endeavored to develop improved methods for writing data to and reading data from the magnetic-recording disk. New ways of servo-control are especially fruitful in overcoming these performance detractors to yield performance advantages that distinguish an HDD product in the marketplace for HDDs created in the continuing evolution of HDD technology.